Correlative studies of Verruca vulgaris by H & E, PAP immunostaining, and electronmicroscopy.

Twenty-one specimens of Verruca vulgaris were used for an investigation to define what portion of the papillomatous structures seen in H & E stain will correspond to the areas of positive staining for papilloma virus antigen utilizing the peroxidase-antiperoxidase immunostaining technique. Vacuolar spaces filled with thready material and large ovoid parakeratotic cells seen in H & E stain stained positively for papilloma virus antigen. In the granular layer, viral antigens stained heavily, the nuclei of cells showing koilocytosis. Both round and irregularly shaped kerathohyaline granules did not stain positively for viral antigen stain. Eight of the 21 specimens showed marked positivity for papilloma virus antigen. Three other cases were positive in only focal sites. Of the 8 immunostained-positive selected cases used for ultrastructural studies, only 2 showed the viral particles. The study suggests that the PAP immunostaining is a more sensitive and yet less cumbersome method than electronmicroscopy for demonstration of papilloma virus.